Mirror Surface Finishing of Silicon Wafer Edge Using Ultrasonic Assisted Fixed-Abrasive CMP (UF-CMP)
Yongbo Wu*, Weiping Yang**, Masakazu Fujimoto*,
and Libo Zhou***
*Department of Machine Intelligence and Systems Engineering, Akita Prefectural University, 84-4 Tsuchiya-ebinokuchi, Yurihonjo, Akita 015-0055, Japan
**Jiangxi Agricultural University, Economic Development District, Nanchang, Jiangxi 330045, China
***Ibaraki University, 4-12-1 Nakanarusawa, Hitachi, Ibaraki 316-8511, Japan
This paper proposes a new method of using Ultrasonic Assisted fixed-abrasive CMP (UA-CMP) to treat silicon wafer edges. In this method, a disc-shaped pellet containing CeO2 abrasives is attached to the end face of an ultrasonic head. The head is elliptically vibrated at an ultrasonic frequency, rotated at a given speed, and pressed against the work-surface of a silicon wafer edge at a certain normal force. In so doing, a solid-state chemical reaction occurs between the CeO2 abrasives and the silicon to form amorphous Ce-O-Si, which is easily removed from the silicon by the mechanical action of the ultrasonic vibration and rotation of the pellet. An experimental apparatus is produced and its fundamental performance is confirmed experimentally. Subsequently, the optimal processing conditions are determined experimentally using the Taguchi method. A mirror edge surface of around Ra3nm with few defects is obtained repeatedly under the optimum conditions.
and Libo Zhou, “Mirror Surface Finishing of Silicon Wafer Edge Using Ultrasonic Assisted Fixed-Abrasive CMP (UF-CMP),” Int. J. Automation Technol., Vol.7, No.6, pp. 663-670, 2013.
-  Electric Journal Co., Ltd., “Semiconductor Fab/Equipment/Facilities,” Tokyo. 2004.
-  M. Narusawa, “Frontier of wafer edge evaluation and polishing,” Electric J., Vol.2, pp. 84-86, 2006.
-  W. Yang, et al., “A new approach to silicon wafer edge treatment by Ultrasonically Assisted Polishing (UAP),” Int. J. Materials and Product Technology, Vol.31, Nos.2/3/4, pp. 159-175, 2008.
-  Y. Wu and W. Yang, “Fundamental investigation of silicon wafer edge treatment by ultrasonically assisted polishing (UAP),” Int. J. Materials and Product Technology, Vol.40, Nos.3/4, pp. 264-276, 2011.
-  A. R. Jones and J. B. Hull, “’Ultrasonic flow polishing,” Ultrasonics, Vol.36, pp. 97-101, 1998.
-  J. Deng and T. Lee, “Effect of ultrasonic surface finishing on the strength and thermal shock behavior of the EDMed ceramic composite,” Int. J. of Machine Tools and Manufacture, Vol.42, pp. 245-250, 2002.
-  H. Hocheng and K. L. Kuo, “Fundamental study of ultrasonic polishing of mold steel,” Int. J. of Machine Tools and Manufacture, Vol.42, pp. 7-13, 2002.
-  L. Zhou, et al., “Research on chemo mechanical grinding (CMG) of Si wafer (1st report),” J. of Japanese Society for Precision Engineering, Vol.68, No.12, pp. 1559-1563, 2002.
-  L. Zhou, et al., “Development of chemo mechanical grinding (CMG) process,” Proc. of Int. Conf. on LEM21, pp. 315-320, 2003.
-  Y. B. Tian, et al., “Elimination of surface scratch/texture on the surface of single crystal Si substrate in chemo-mechanical grinding (CMG) process,” Applied Surface Science, Vol.255, pp. 4205-4211, 2009.
-  S. Kamiya, et al., “Study on reaction mechanism of Si and pure CeO2 for chemical-mechanical-grinding process,” Proc. of the 1st Int. Conf. on Nano-manufacturing (nanoMan’2008), 2008.
-  L. Zhou, et al., “Defect-free fabrication for single crystal silicon substrate by chemo-mechanical grinding,” Annals of the CIRP 2006 – Manufacturing Technology, Vol.15, pp. 313-316, 2006.
-  H. Huang, et al., “Characteristics of silicon substrates fabricated using nanogrinding and chemo-mechanical grinding,” Materials Science and Engineering A, Vol.479, pp. 373-379, 2008.
-  Y. Wu, et al., “Performance improvement of chemo-mechanical grinding in single crystal silicon machining by the assistance of elliptical ultrasonic vibration,” Int. J. Abrasive Technology, Vol.4, No.2, pp. 117-131, 2011.
-  T. Hoshino, et al., “Mechanism of polishing of SiO2 films by CeO2 particles,” J. Non-Crystalline Solids, Vol.283, pp. 129-136, 2001.